<div class="waper">
    <div>
        <h2>Promise 学习</h2>
        <button (click)="testPromise()">testPromise</button>
    </div>
    <div>
        <h2>Generator 学习</h2>
        <button (click)="testGenerator()">testGenerator</button>
    </div>
    <div>
        <h2>async 学习</h2>
        <button (click)="testasync()">testasync</button>
    </div>
    <div>
        <h2>class 学习</h2>
        <button (click)="testClass()">testClass</button>
    </div>
    <div>
        <h2>extends 学习</h2>
        <button (click)="testExtends()">testExtends</button>
    </div>
</div>